1. Field of the Invention
The present invention relates generally to Ethernet systems and, more particularly, to a system and method for controlling a physical layer device attached to a media access control interface for energy efficient Ethernet.
2. Introduction
Energy costs continue to escalate in a trend that has accelerated in recent years. Such being the case, various industries have become increasingly sensitive to the impact of those rising costs. One area that has drawn increasing scrutiny is the IT infrastructure. Many companies are now looking at their IT systems' power usage to determine whether the energy costs can be reduced. For this reason, an industry focus on energy efficient networks has arisen to address the rising costs of IT equipment usage as a whole (i.e., PCs, displays, printers, servers, network equipment, etc.).
One area that has shown the potential for cost and energy savings is efficient link utilization. Most network links are typically in an idle state between sporadic bursts of data. The overall link utilization is therefore relatively low. In one solution, the link rate can be reduced when the high data capacity is not needed, thereby saving energy. In other words, a link can use a high data rate when data transmission needs are high, and use a low data rate when data transmission needs are low. In another solution, a link can be designed to enter into a low power idle mode where the active channel is turned silent. While these solutions can provide significant energy savings, what is needed is a mechanism for controlling physical layer devices that implement efficient link utilization.